Abstract
The relevance of research is due to the need to improve individual elements of agrotechnology for medick and perennial meadow-grasses cultivation depending on the background of mineral nutrition, and for the creation of highly productive herbage in the gray forest soils of the southwestern part of the Central region of the Russian Federation. Perennial legumes in single-species and heterogeneous crops are the main components in solving the problem of vegetable protein in the production of the highest quality feed. The methodology of field experiments is based on the principle of intensification and biologization of agriculture. The research aims at developing elements of agricultural technologies for the cultivation of perennial grasses in single-species and heterogeneous crops and at improving the biochemical composition of forages, depending on both the species composition of the grass mixture and the effect of the background of mineral fertilizers on the yield in single-species and heterogeneous field agrocenoses. The research methods were field, laboratory, and statistical. Field studies were carried out on the experimental field of Bryansk State Agrarian University using a modern assortment of medick and perennial meadow-grasses on various backgrounds of mineral fertilizers. In the grass mixtures, the legume component varied from 40 to 50%. Sowing was carried out under the cover of one-year-old Westerwolds ryegrass (Lolium multiflorum Lam. var. westerwoldicum Wittm). Medick (Medicago varia Mart.) was used as the legume component. Meadow-grasses are represented by timothy (Phleum pratense L.), meadow fescue (Festuca pratensis Huds.), cat grass (Dactylis glomerata L.), and awnless brome (Bromus inermis). The formation of the yield of green mass and dry matter of medick and perennial meadow-grasses mixtures is justified by the background of mineral nutrition and the species composition of cultivated grass mixtures. On average, over the years of field experiments, the maximum yield (45.32 t/ha) of green mass and of dry matter (11.33 t/ha) was obtained in the variant of medick-fescue grass mixture against the background of prolonged action of Borofoska in combination with annual nitrogen fertilization at the dose N30. Under the influence of mineral fertilizers, an improvement in the biochemical composition of dry matter of heterogeneous crops of legume-perennial meadow-grasses was noted. The highest indices of nutrients were found in the forage mass of the medick-timothy grass mixture.

Key words: biochemical composition, medick, mixed heterogeneous agrocenoses, mineral fertilizers, productivity.